1. Field of the Invention
The present invention relates generally to the field of pushbutton radio tuners, and specifically to an improved tuning drive gear and clutch assembly, suitable for a range of front panel configurations.
2. Prior Art
In the past, a new tuner assembly was designed for each new radio design. When it becomes desirable to provide a tuner usable in a number of radio designs, compromises were made. Most common of these was making the position of the tuning knob shaft changeable without complete redesign of the tuner. This was typically accomplished by inserting some type of direction-changing device, such as a universal joint, in the tuner control shaft to allow the shaft position to be varied. This meant, however, that the support point of the pinion gear remained unchanged while its angular position moved. Since this created both cross-cutting and severe binding problems between the metal piece of the pinion gear and the resilient plastic of the crown gear, the next solution, i.e., making the teeth of the crown gear radially narrower, merely reduced gear binding at the cost of accelerated crown gear wear and eventual tuner drive failure.
As a corollary, it is advantageous to have the drive and clutch mechanism completely assembled and adjusted, and needing merely to be locked down and put into position at the time of tuner assembly.